Windows activation help

ok i have windows xp homeedition and it has been asking me to activate it for the last 30 days and today the days finally ran our, now before i can login it says i need to activat it, so i go and and click activate, the activation screen comes up and it says its already activated, then it takes me back to the login screen and the thing happens all over agian

if you do not understand what i typed up there i can re-type it in better.

does anyone no a way around this or how i can fix, without having to re-install winodws all over agian

I don't really think it's fair sometimes, personally speaking, but none the less that's the way it is and so installing more than one machine with the same copy, bought or otherwise is piracy (unless using a Volume License key purchased from MS, but that's out of the reach of most of us mere mortals)